HIGH LIVING: One of the ways Erin Boyle and fiancé James Casey have survived living in their cozy, 240-square-foot Brooklyn Heights unit is by building a loft bed above their stove.Dana Sauchelli

(Dana Sauchelli)

(Dana Sauchelli)

(Dana Sauchelli)

(Dana Sauchelli)

HIGH LIVING: One of the ways Erin Boyle and fiancé James Casey have survived living in their cozy, 240-square-foot Brooklyn Heights unit is by building a loft bed above their stove. (Dana Sauchelli)

HIGH LIVING: One of the ways Erin Boyle and fiancé James Casey have survived living in their cozy, 240-square-foot Brooklyn Heights unit is by building a loft bed above their stove. (Dana Sauchelli)

This is how you make a “micro-unit” apartment work!

For the past year, writer Erin Boyle, 28, and biologist James Casey, 30, have lived in a 240-square-foot apartment in Brooklyn Heights — and they still plan on getting married next month.

The couple revealed their “dungeon-esque” living space a day after Mayor Bloomberg said he wanted developers to build “mico-unit” apartments — from 275 to 300 square feet — for people who are single or live with a partner.

Boyle says she and her fiancé have a system to keep the peace in such close quarters.

The first and most important rule is keeping the place tidy.

“We have kind of figured out the nooks and crannies and where things go,” like keeping a wine crate beneath their love seat for annoying items like cellphone chargers and mail, Boyle said.

“We keep things neat and organized so there is space to walk around or we wouldn’t be able to live here,” she said of the $1,500-a-month studio.

When it comes to furniture, they try to ditch an item every time they bring in something new.

They’re careful about “not filling it with stuff that we don’t need or use. We are constantly editing what we have here to make sure that it is working,” Boyle said.

It’s also important to build up — they have a loft bed above their cooking stove.

“It’s not too bad; it might be worse if we were beside the stove,” Boyle said.

And they reduce arguments by compromising.

When Casey wanted to bring his surfboard into the apartment, they first stashed it in the shower.

“He’s a surfer, so there was no way we were going to get rid of it,” Boyle said.

“We left it in the bathtub and showered with it but then we realized that it was more of a burden,” Boyle said — so they agreed to clear out a corner instead of getting rid of it.

Even city shrinks said making small spaces work is hard — but not impossible, because humans are “very adaptable animals.”

“Small space by themselves don’t create a problem,” said Dr. Robert Schachter. “It’s whether there are problems that come into the space.”